The present invention relates generally to medical devices and in particular aspects to apparatuses and methods for treating fistulae.
As further background, fistulae can occur for a variety of reasons such as but not limited to as a congenital defect, as a result of inflammatory bowel disease such as Chron's disease, irradiation, trauma such as childbirth, or as a side effect from a surgical procedure. Additionally, several different types of fistulae can occur in humans, for example, urethro-vaginal fistulae, vesico-vaginal fistulae, tracheo-esophageal fistulae, gastrointestinal fistulae including but not limited to gastrocutaneous, enterocutaneous and colocutaneous fistulae, and any number of anorectal fistulae such as recto-vaginal fistula, recto-vesical fistulae, recto-urethral fistulae, and recto-prostatic fistulae.
A gastrointestinal fistula is an abnormal passage that leaks contents of the stomach or the intestine (small or large bowel) to other organs, usually other parts of the intestine or the skin. For example, gastrojejunocolic fistulae include both enterocutaneous fistulae (those occurring between the skin surface and the intestine, namely the duodenum, the jejunum, and the ileum) and gastric fistulae (those occurring between the stomach and skin surface). Another type of fistula occurring in the gastrointestinal tract is an enteroenteral fistula, which refers to a fistula occurring between two parts of the intestine. Gastrointestinal fistulae can result in malnutrition and dehydration depending on their location in the gastrointestinal tract. They can also be a source of skin problems and infection. The majority of these types of fistulae are the result of surgery (e.g., bowel surgery), although sometimes they can develop spontaneously or from trauma, especially penetrating traumas such as stab wounds or gunshot wounds. Inflammatory processes, such as infection or inflammatory bowel disease (Crohn's disease), may also cause gastrointestinal fistulae. In fact, Crohn's disease is the most common primary bowel disease leading to enterocutaneous fistulae, and surgical treatment may be difficult because additional enterocutaneous fistulae develop in many of these patients postoperatively.
The path which fistulae take, and their complexity, can vary. A fistula may take a take a “straight line” path from a primary opening to a secondary opening, known as a simple fistula. Alternatively, a fistula may comprise multiple tracts ramifying from a primary opening and have multiple secondary openings. This is known as a complex fistula.
Current treatment options for gastrointestinal fistulae vary. Depending on the clinical situation, patients may receive IV nutrition and go a period of time without food to try to get the fistula to close on its own. Indeed, nonsurgical therapy may allow spontaneous closure of the fistula, although this can be expected less than 30% of the time according to one estimate. A variable amount of time to allow spontaneous closure of fistulae has been recommended, ranging from 30 days to 6 to 8 weeks. During this time, external control of the fistula drainage can prevent skin disruption and provide a guideline for fluid and electrolyte replacement. In some cases, surgery is necessary to remove the segment of intestine involved in a non-healing fistula.
When surgery is deemed necessary, one operation for fistula closure is resection of the fistula-bearing segment and primary end-to-end anastamosis. The anastomosis may be reinforced by greater omentum or a serosal patch from adjacent small bowel. Still other methods for treating fistulae involve injecting sclerosant or sealant (e.g., collagen or fibrin glue) into the tract of the fistula to block the fistula. Closure of a fistula using a sealant is typically performed as a two-stage procedure, including a first-stage seton placement and injection of the fibrin glue several weeks later. This allows residual infection to resolve and to allow the fistula tract to “mature” prior to injecting the sealant. If sealant or sclerosant were injected as a one-stage procedure into an “unprepared” or infected fistula, this may cause a flare-up of the infection and even further abscess formation.
There remain needs for improved and/or alternative fistula plugs, as well as apparatuses and methods for delivering fistula plugs into the body. The present invention is addressed to those needs.